You may play as a guest or create an optional Google-linked profile. First registration receives 2,000 in-game crystals once per account. Nicknames are public and must be unique.
Cloud saves and rankings need an internet connection and are subject to service availability. Keep your local save until cloud synchronization completes. The leaderboard is based on client-reported game events.
The two-confirmation reset removes wave progress, upgrades and combat achievements. It preserves account identity and returns the total crystals ever earned or purchased to the balance. Repeating a reset alone does not create extra crystals.
Google Play controls update availability, purchases and installation confirmation. Update notifications are optional and background delivery may be delayed by Android.